The present invention relates to a main body structure for an underground parking lot and the underground parking lot constructed by using the structure, in which structure the outer periphery of a main body is formed in a substantially cylindrical shape.
In recent years, in urban areas, such a serious problem arises as to get a site for a building. Particularly, it is getting in an extremely difficult situation to secure a space for parking cars.
For improving the accommodation or parking capacity for vehicles of a small site, it is effective to employ such a structure which is capable of accommodating vehicles in three dimensions. For this end, as is well known, there have been provided a mechanical type parking tower which has an elevator mechanism or the like to accommodate plural cars in a three-dimensional manner, a self-traveling type three-dimensional parking lot which has plural floors constructed on the ground and ramps for interconnecting the floors and in which drivers themselves drive their vehicles to transport the same to any floor, an underground parking lot which is constructed in three dimensions by utilizing the underground of a site for a building, or the like.
Among the above three-dimensional parking lots, the underground type particularly surpasses in making effective use of the site, because it utilizes the underground of a building and requires no new site for the parking lot. Further, as this type parking lot, so to say, integrally exists within the building which has residential floors, when users of this parking lot have somethings to do in this building, they can shorten time for movement. This is particularly convenient for them.
In constructing the underground type parking lot, however, problems arise as follows.
Namely, a conventional underground parking lot has generally been designed to have a main body formed in a rectangular shape in cross section. However, in the underground parking lot thus designed in the rectangular shape, according as its depth in the ground increases, a large sectional force acts over its structural body due to an earth pressure of the ground, a water pressure and so on. When constructing this type parking lot, therefore, it is required to provide timbering, struts or the like, taking time and labor and increasing cost. Further, even when no timbering is used, it is necessary to use a caisson type or an ultra thick wall type underground continuous wall. Thus, the underground parking lot has many executive restrictions in the term of working, the cost of construction and so forth.
Moreover, since the conventional underground parking lot of the rectangular shape has the difficulty in being made large in cross section as described above, there are many cases where the underground parking lot is small in plan size as compared with the building which is to be constructed on the parking lot. Therefore, it is not attainable to use the site to the maximum extent, and in addition, it is still necessary to provide piles or the like for supporting the building on the outside of the underground parking lot.